Mechanism Research And Parameter Optimization Of Jetting In Injection Molding

Jetting phenomenon is a common phenomenon, which can cause products defect in injection molding process. When plastic melt flow through the narrowing ranges such as the nozzle, runner, gate, and etc. at high speed, then suddenly flow into the open, relatively wide areas, the melt material flows along the flow direction like a snake bending forward, and cools rapidly after contacting mould surface. Due to this part of the material can’t melt well with the subsequent fusion flowing into the cavity, it cause the obvious jetting lines in products. Jetting lines can cause harmful effects to the appearance of the plastic parts and even mechanical properties in many cases.Now, some scholars research maturely some common defects, such as short, bubble, warping, weld line in injection molding process. Scholars study the causes of the jetting and also put forward the corresponding solutions in the research of jetting phenomenon. However, the research is mainly based on production experience and experimentation, and rarely used the software to simulate the complex flow behavior.This paper explores the relationship between the gate front end and back end radius, injection velocity, melt temperature and other factors with jetting phenomenon, a cuboid as an example. The paper draws the best molding parameters combination by the orthogonal experiment. The paper then simulates under the combination parameters; there are no jetting lines, so the quality of product is improved.